Motor compressor

ABSTRACT

In a motor compressor, a housing forms a fitting surface at an outer peripheral surface of the housing and a plurality of insertion holes extending through the housing at the fitting surface. A compression mechanism is accommodated in the housing. An electric motor is accommodated in the housing for driving the compression mechanism. A plurality of terminal pins transmits electric current to the electric motor. A terminal substrate is fastened to the housing by a bolt so as to be fixed to the fitting surface and forms a plurality of holes. The terminal pin is inserted into each hole of the terminal substrate while being fixedly supported on the terminal substrate so as to be insulative and airtight. The insertion holes correspond to the holes. The gasket is interposed between the fitting surface and the terminal substrate, while each terminal pin is inserted into the corresponding insertion holes.

BACKGROUND OF THE INVENTION

The present invention relates to a motor compressor including acompression mechanism and an electric motor as a drive source of thecompression mechanism in a housing of the motor compressor.

Such a motor compressor has a plurality of terminal pins fixed to andextending through a housing of the motor for supplying electric currentto an electric motor which is accommodated in the housing.

A structure for fixing the terminal pins to the housing is disclosed inUnexamined Japanese Patent Publication No. 2002-155862, in which aplurality of through holes is formed in the housing, and each terminalpin is supported in the housing through an O-ring and a bushing servingas an insulating member and fixed by a circular clip engaged in thethrough hole.

Another fixing structure is disclosed in Unexamined Japanese PatentPublication No. 2002-369439, according to which a mounting flange of aterminal having a plurality of terminal pins connected thereto is heldtogether with an O-ring between a connecting port formed in a housingand a separate member to be connected to the connecting port to be fixedto the housing.

Carbon dioxide refrigerant gas is used under a pressure which is aboutten times as high as a fluorocarbon refrigerant gas. Additionally,carbon dioxide refrigerant gas is more permeable into a rubber sealmember than fluorocarbon refrigerant gas and, therefore, there is aproblem that the carbon dioxide refrigerant gas leaks outside thehousing.

In the case of the fixing structure disclosed in Unexamined JapanesePatent Publication No. 2002-155862, when applied to a compressor usingcarbon dioxide refrigerant gas, the strength of the circular clip is notsufficient in view of the pressure of the refrigerant gas which acts oneach terminal pin. Furthermore, carbon dioxide refrigerant gas leaksoutside the housing through the O-ring.

In the case of the fixing structure disclosed in Unexamined JapanesePatent Publication No. 2002-369439, since the connecting port whichreceives the terminal mounting flange fixedly supporting a plurality ofthe terminals and the separate member is formed in the housing, therigidity of the connecting port and its surrounding portion is reduced.For compensation for such reduction of rigidity, the housing wall needsto be thickened. The compressor having such thickened housing wallbecomes larger, and the weight thereof increases, accordingly.Therefore, there has been a need for providing a motor compressor whichensures a sufficient strength against pressure without making a terminalpin fixing portion larger and reliably prevents leakage of refrigerantgas even when carbon dioxide is used as refrigerant gas.

SUMMARY OF THE INVENTION

In accordance with the present invention, a motor compressor has ahousing, a compression mechanism, an electric motor, a plurality ofterminal pins, a terminal substrate and a gasket. The housing forms afitting surface at an outer peripheral surface of the housing and aplurality of insertion holes extending through the housing at thefitting surface. The compression mechanism is accommodated in thehousing. The electric motor is accommodated in the housing for drivingthe compression mechanism. A plurality of the terminal pins transmitselectric current to the electric motor. The terminal substrate isfastened to the housing by a bolt so as to be fixed to the fittingsurface and forms a plurality of holes. The terminal pin is insertedinto each hole of the terminal substrate while being fixedly supportedon the terminal substrate so as to be insulative and airtight. Theinsertion holes of the fitting surface correspond to the holes. Thegasket is interposed between the fitting surface and the terminalsubstrate, while each terminal pin is inserted into the correspondinginsertion holes of the fitting surface.

Other aspects and advantages of the invention will become apparent fromthe following description, taken in conjunction with the accompanyingdrawings, illustrating by way of example the principles of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the present invention that are believed to be novel areset forth with particularity in the appended claims. The inventiontogether with objects and advantages thereof, may best be understood byreference to the following description of the presently preferredembodiments together with the accompanying drawings in which:

FIG. 1 is a longitudinal cross-sectional view of a motor compressoraccording to a preferred embodiment of the present invention;

FIG. 2 is a partially enlarged longitudinal cross-sectional view of FIG.1;

FIG. 3 is a partially enlarged cross-sectional view about a planeperpendicular to a rotary shaft according to the first preferredembodiment of the present invention; and

FIG. 4 is an exploded perspective view of a structure for fixingterminal pins.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A preferred embodiment of a scroll type motor compressor for use in avehicle air conditioner according to the present invention will now bedescribed with reference to FIGS. 1 through 4.

As shown in FIG. 1, a motor compressor 10 has a housing 11 whichincludes a first housing component 12 and a second housing component 13both of which are made of die casting aluminum alloy, and the housing 11is formed by connecting the first housing component 12 and the secondhousing component 13 together. The first housing component 12 is shapedinto a cylinder with a bottom at one end thereof, and includes alarger-diameter cylindrical portion 14, a smaller-diameter cylindricalportion 15 and a bottom portion 16 which closes one end of thesmaller-diameter portion 15. The second housing component 13 is shapedinto a cylinder with a bottom at one end thereof, including acylindrical portion 17 having substantially the same diameter of thelarger-diameter cylindrical portion 14 and a bottom portion 18 whichcloses one end of the cylindrical portion 17.

The inner peripheral surface of the larger-diameter cylindrical portion14 of the first housing component 12 has a smaller-diameter portion 14 aon the side of the smaller-diameter cylindrical portion 15, alarger-diameter portion 14 b on the side of the open end and a retainingsurface 14 c at a stepped boundary between the smaller-diameter portion14 a and the larger-diameter portion 14 b. A connecting surface 13 a ofthe second housing component 13, against which a connecting surface 12 aof the first housing component 12 is clamped, is formed to have anannular portion which is extended radially inner than the connectingsurface 12 a such that the annular portion partially faces the retainingsurface 14 c.

The first housing component 12 has formed integrally therewith aplurality of connecting portions 19 spaced at intervals on the outerperipheral surface of the larger-diameter cylindrical portion 14adjacent to the open end side of the first housing component 12. Thesecond housing component 13 has also formed integrally therewith aplurality of similar connecting portions 20 on the outer peripheralsurface of the cylindrical portion 17 at spaced positions correspondingto the connecting portions 19. The first and second housing components12, 13 are fastened together integrally at their respective connectingportions 19, 20 by bolts 21 such that the connecting surface 12 a of thefirst housing component 12 and the connecting surface 13 a of the secondhousing component 13 are pressed against each other through an annulargasket 22. The housing 11 thus constructed forms therein a sealed space23. It is noted that the connecting surface 13 a of the second housingcomponent 13 and the gasket 22 have annular portions which are extendedradially inner than the connecting surface 12 a of the first housingcomponent 12.

The first housing component 12 includes integrally therewith acylindrical shaft support portion 24 at the center of the bottom portion16 inside the first housing component 12. On the other hand, a shaftsupport member 25 is fitted in the larger-diameter portion 14 b of thelarger-diameter cylindrical portion 14 of the first housing component12. The shaft support member 25 includes a cylindrical portion 26forming therein a through hole 26 a and a flange 27 which is formedintegrally therewith at one end of the cylindrical portion 26. The shaftsupport member 25 is positioned in the second housing component 13 withthe end surface of the flange 27 set in contact with the retainingsurface 14 c.

The compressor 10 includes a rotary shaft 28 which has one end receivedin the first housing component 12 and rotatably supported by a bearing29 of the shaft support portion 24. The other end of the rotary shaft 28is rotatably supported by a bearing 30 in the through hole 26 a of theshaft support member 25. A stator core 32, which is wound by an excitercoil 31, is fixedly fitted inside of the smaller-diameter cylindricalportion 15 of the first housing component 12. On the other hand, a rotor33 made of a multipolar magnet is fixedly supported by the rotary shaft28 so as to face the stator core 32. The exciter coil 31, the statorcore 32 and the rotor 33 cooperate to form an inner rotor type brushlessmotor 34.

A scroll type compression mechanism 35 is provided inside thelarger-diameter cylindrical portion 14 of the first housing component12. That is, a fixed scroll member 36 is fixedly fitted in thelarger-diameter portion 14 b of the first housing component 12. Thefixed scroll member 36 includes a disc-shaped base plate 37, acylindrical outer peripheral wall 38 formed integrally with the baseplate 37 at the outer peripheral region thereof, and a fixed scroll wall39 formed also integrally with the base plate 37 inside the outerperipheral wall 38. The outer peripheral wall 38 of the fixed scrollmember 36 and the flange 27 of the shaft support member 25 areinterposed between the retaining surface 14 c of the first housingcomponent 12 and the radially inner portion of the joint surface 13 a ofthe second housing component 13 with the radially inner annular portionof the gasket 22 held between the joint surface 13 a of the secondhousing component 13 and the base plate 37 of the fixed scroll member36.

A crankshaft 40 is formed on the end surface of the rotary shaft 28adjacent to the fixed scroll member 36. A bushing 41 having a balanceweight 41 a is fixedly fitted over the crankshaft 40. A movable scrollmember 42 facing the fixed scroll member 36 is rotatably supported bythe bushing 41 through a bearing 43 disposed in the boss 42 a of themovable scroll member 42 for rotation relative to the fixed scrollmember 36. The crankshaft 40, the bushing 41 and the bearing 43cooperate to form an orbiting mechanism for the movable scroll member 42to orbit by rotation of the rotary shaft 28.

The movable scroll member 42 includes a disc-shaped base plate 44 and amovable scroll wall 45 which is formed integrally with the base plate44. The fixed scroll wall 39 of the fixed scroll member 36 and themovable scroll wall 45 of the movable scroll member 42 engage with eachother and the distal ends of the fixed and movable walls 39, 40 are incontact with the base plates 44, 37, respectively, through seal members(not shown). The fixed scroll member 36 and the movable scroll member 42cooperate to define compression chambers 47. The innermost compressionchamber 47 is communicable with the backside of the base plate 37, thatis, the inner space of the second housing component 13, through adischarge port 37 a which is formed at the center of the base plate 37of the fixed scroll member 36. It is noted that the fixed scroll member36 is provided with a known reed valve (not shown) at its back surfacefor opening and closing the discharge port 37 a and a retainer forregulating the opening degree of the reed valve. The outer peripheralwall 38 of the fixed scroll member 36 and the outermost peripheralportion of the movable scroll wall 45 of the movable scroll member 42define therebetween a suction chamber 48. The suction chamber 48 is incommunication with the inner space of the brushless motor 34 through apath (not shown), and is connected to an evaporator of an externalrefrigerant circuit (not shown) through a suction port 49 which isformed in the first housing component 12 for communication between theinner space and the outside of the housing 11.

A plurality of fixed pins 50 is fixedly connected to the base plate 37of the fixed scroll member 36 on a common circle, and a plurality ofmovable pins 51 is fixedly connected to the base plate 44 of the movablescroll member 42 so as to correspond with the respective fixed pins 50.The fixed pins 50 and the movable pins 51 cooperatively form a knownrotation prevention mechanism of the movable scroll member 42.

The second housing component 13 forms therein a discharge chamber 60into which compressed refrigerant gas is discharged through thedischarge port 37 a of the fixed scroll member 36. The discharge chamber60 is in communication with the external refrigeration circuit outsideof the housing 11 through a path (not shown) which extends through thesecond housing component 13.

As shown in FIG. 1, the first housing component 12 includes a seat 70integrally therewith at the outer periphery of the larger-diametercylindrical portion 14. The seat 70 includes at its top surface afitting surface 71 to which a terminal substrate 73 for fixedlysupporting three terminal pins 72 is fixedly connected by four bolts 75through a gasket 74. The terminal substrate 73 has a rectangularprojected plan view in the vertical direction of FIG. 1 (or arectangular shape), and the longitudinal direction of the rectangularprojected plan view (or the rectangular shape) is located along thecircumferential direction of the housing 11.

As shown in FIGS. 2 through 4, the terminal substrate 73 includestherein three holes 76 which are spaced at the same interval on a commoncircumference and through which the terminal pins 72 are respectivelyinserted. The terminal pin 72 inserted through each hole 76 is fixedlysupported by an insulating member 78 which is made of glass and fills agap between the terminal pin 72 and the hole 76 so as to be insulativeagainst the terminal substrate 73 and to seal the hole 76 airtightly.

As shown in FIG. 4, the gasket 74 includes therethrough three holes 79which have the same diameter as the holes 76 of the terminal substrate73 so as to correspond to the holes 76. Each hole 79 has a known bead 79a at its circumference. The gasket 74 further includes therethrough fourholes 80 for receiving therethrough the bolts 75 at positionscorresponding to the holes 77 of the terminal substrate 73.

The seat 70 includes therethrough three insertion holes 81 which havethe same diameter as the holes 76 of the terminal substrate 73 so as tocorrespond to the holes 76 and which extend also through the firsthousing component 12. The seat 70 also includes therein four threadedholes 82 which correspond to the holes 77 of the terminal substrate 73and which receive therein the bolts 75, respectively.

As shown in FIGS. 1 through 3, the terminal substrate 73 is fastened tothe fitting surface 71 of the seat 70 by four bolts 75 through thegasket 74. Each terminal pin 72, which is fixedly supported by theterminal substrate 73, is inserted through the hole 79 of the gasket 74and into the insertion hole 81 of the seat 70, respectively. Thus, theinsertion holes 81 which face their corresponding holes 76 in theterminal substrate 73 are separately sealed from each other by thegasket 74.

In the housing 11, the distal end of each terminal pin 72 is connectedto a cluster block 83 which is located inside the brushless motor 34.Outside the housing 11, a cable connector is connected to each terminalpin 72 for supplying three-phase alternating current from a three-phaseinverter circuit (not shown). Three-phase alternating current suppliedfrom the three-phase inverter circuit is fed to the three-phase excitercoil 31 through the three terminal pins 72 and the cluster block 83.

According to the preferred embodiment, the following advantageouseffects are obtained.

(1) Three holes 76 are separately formed in one terminal substrate 73which is fastened by four bolts 75 to the fitting surface 71 of the seat70 formed on the outer peripheral surface of the housing 11. Theterminal pin 72 is inserted through and fixedly supported by each hole76 such that the terminal pin 72 is insulated and sealed airtight. Onthe other hand, the insertion holes 81 formed in the fitting surface 71of the seat 70 and extending through the housing 11 are providedseparately so as to correspond to the respective holes 76 of theterminal substrate 73. Then, three terminal pins 72 are inserted throughthe corresponding insertion holes 81 with the gasket 74 interposedbetween the fitting surface 71 and the terminal substrate 73.

Since the insertion holes 81 for receiving therein the terminal pins 72which are fixedly supported by the terminal substrate 73 are separatelyformed in the fitting surface 71 of the seat 70 formed on the housing11, the rigidity of the seat 70 and its vicinities will be hardlyreduced. Therefore, even if the pressure of the refrigerant gas in thehousing 11 is high, the seat 70 and its vicinities are hardly deformedand, therefore, a gap will not be formed between the fitting surface 71and the terminal substrate 73. Accordingly, the seat 70 and itsvicinities need not be thickened, so that the housing 11 does notincrease its size and weight. Furthermore, since the gasket 74 providesan airtight seal between the fitting surface 71 and the terminalsubstrate 73, the amount of refrigerant gas leaked out of the housing 11is less than the case wherein an O-ring is used. As a result, theleakage of refrigerant gas through the fixing portion of the terminalpins 72 is much reduced without increasing the size of the compressor10.

(2) The gasket 74 has three holes 79 corresponding to the three terminalpins 72. Accordingly, a plurality of the insertion holes 81 which facesthe respective holes 79 are isolated from each other with separatesealing, so that the area of the terminal substrate 73 receiving thepressure of refrigerant gas through the insertion holes 81 reduces.Therefore, the terminal substrate 73 is prevented from being deformedunder the influence of the pressure of refrigerant gas, so that theterminal substrate 73 may be made thinner and, therefore, the fittingportion of the terminal substrate 73 is made smaller.

(3) The terminal substrate 73 is fastened by the bolts 75 to thesubstantially cylindrical housing 11 at each end of the terminalsubstrate 73 extending along the circumferential direction of thehousing 11. Thus, a portion of the housing 11 corresponding to the endsof the terminal substrate 73 in the longitudinal direction thereofbecomes thick and, therefore, the threaded holes 82 may be formed deepenough for fastening by bolts 75 without thickening the fitting portionof the terminal substrate 73. That is, the fitting portion of theterminal substrate 73 is made smaller.

(4) The housing 11 is made of aluminum alloy. In the compressor 10 inwhich the housing 11 is made of aluminum alloy having a lower strengththan ferrous material, the seat 70 which forms the fitting surface 71and its vicinities tend to be easily deformed under the influence of thepressure of refrigerant gas. Therefore, the advantageous effectmentioned under the above item (1) is more conspicuous in the compressor10 having the housing 11 which is made of aluminum alloy.

(5) The compressor 10 employs carbon dioxide as refrigerant gas. In thecompressor employing carbon dioxide which is used under a pressure whichis about ten times as high as the fluorocarbon refrigerant gas, the seat70 which forms the fitting surface 71 and its vicinities tend to beeasily deformed due to the pressure of refrigerant gas. Therefore, theabove mentioned advantageous effect (1) is more conspicuous in thecompressor employing carbon dioxide as refrigerant gas.

The present invention is not limited to the embodiments described abovebut may be modified into the following alternative embodiments.

In an alternative embodiment to the above preferred embodiment, thegasket 74 has one hole for inserting three terminal pins 72 instead ofhaving three holes 79.

In an alternative embodiment to the above preferred embodiment, theshape of the terminal substrate 73 as seen from the top of FIG. 1 issquare, ellipse, circle, polygon or the like instead of the rectangle.In this case, the seat 70 and the fitting surface 71 have a similarshape.

In an alternative embodiment to the above preferred embodiment, theterminal pins 72 are arranged in the terminal substrate 73 in alignmentwith each other or on a predetermined circular arc, instead of arrangingthe terminal pins 72 in the terminal substrate 73 on a common circle.

In an alternative embodiment to the above preferred embodiment,intervals between the adjacent terminal pins 72 are different intervals,instead of arranging the terminal pins 72 in the terminal substrate 73at substantially the same intervals.

In an alternative embodiment to the above preferred embodiment, thebottom portion 16 of the first housing component 12 has a seat whichforms a fitting surface to which the terminal substrate is fastened bybolts.

In an alternative embodiment to the above preferred embodiment, thehousing 11 is not limited to the construction having two membersincluding the first housing component 12 and the second housingcomponent 13, but is constituted of three or more members.

In an alternative embodiment to the above preferred embodiment, theelectric motor is not limited to a brushless motor, but a DC motor isusable.

In an alternative embodiment to the above preferred embodiment, thepresent invention is applied to a compressor having a compressionmechanism such as a piston type, a vane type and a helical type.

In an alternative embodiment to the above preferred embodiment, thepresent invention is applied to a motor compressor which employs afluorocarbon refrigerant as refrigerant gas.

Therefore, the present examples and embodiments are to be considered asillustrative and not restrictive, and the invention is not to be limitedto the details given herein but may be modified within the scope of theappended claims.

1. A motor compressor comprising: a housing forming a fitting surface atan outer peripheral surface of the housing and a plurality of insertionholes extending through the housing at the fitting surface; acompression mechanism accommodated in the housing; an electric motoraccommodated in the housing for driving the compression mechanism; aplurality of terminal pins transmitting electric current to the electricmotor; a terminal substrate fastened to the housing by a bolt so as tobe fixed to the fitting surface, the terminal substrate forming aplurality of holes, the terminal pin being inserted into each hole ofthe terminal substrate while being fixedly supported on the terminalsubstrate so as to be insulative and airtight, the insertion holes ofthe fitting surface correspond to the holes; and a gasket interposedbetween the fitting surface and the terminal substrate, while eachterminal pin is inserted into the corresponding insertion holes of thefitting surface.
 2. The motor compressor according to claim 1, whereinthe gasket independently forms a plurality of holes which correspondwith the terminal pins.
 3. The motor compressor according to claim 1,wherein the housing has a substantially cylindrical shape, the terminalsubstrate being fastened to the housing by the bolts at each end thereofin a circumferential direction of the housing.
 4. The motor compressoraccording to claim 1, wherein the housing is made of aluminum alloy. 5.The motor compressor according to claim 1, wherein the motor compressoremploys carbon dioxide as refrigerant.
 6. The motor compressor accordingto claim 1, wherein a plurality of the terminal pins is arranged atsubstantially the same interval on a substantially common circle in theterminal substrate.
 7. The motor compressor according to claim 1,further comprising: an insulating member filling a gap between theterminal pins and the holes so as to be insulative against the terminalsubstrate and to seal the hole airtightly.
 8. The motor compressoraccording to claim 7, wherein the insulating member is made of glass. 9.The motor compressor according to claim 1, wherein the terminalsubstrate has a rectangular shape, a longitudinal direction of therectangular shape extending along a circumferential direction of thehousing.